Manson's schistosomiasis in the undernourished mouse: some recent findings

Abstract

This paper deals with current knowledge of the interrelationships between Schistosoma infection and malnutrition. It emphasizes the relevance of these investigations in the face of dynamic and evolving changes occurring in population diets and changes in the epidemiological patterns of schistosomiasis in endemic countries. The paper further discusses the basis for continuing the studies on this subject and the reasons why it represents a misunderstood association. This review also focuses on the cellular and humoral immune responses in the undernourished mouse model infected with Schistosoma mansoni, with updated information on the immune response in wild-type and iNOS knockout mice concerning soluble egg antigen specific antibodies and kinetics of IFN-γ, IL-4, IL-10 and IL-13 cytokines, in the chronic phase of Manson's schistosomiasis. There is indication that schistosome-infected undernourished mice are able to develop a humoral immune response, but antibody titres are much lower than in the control animals. Cytokine production (IFN-γ, IL-4, IL-10) is lower in the undernourished mice, but as infection progresses to the chronic phase its kinetics run an antagonistic course when compared to that of well-nourished animals. Marked variation in the secretion of IL-13 (a fibrogenic cytokine) could explain why undernourished mice do not develop liver "pipe-stem" fibrosis described in previous papers on well-nourished animals

Low transformation growth factor-β1 production and collagen synthesis correlate with the lack of hepatic periportal fibrosis development in undernourished mice infected with Schistosoma mansoni

“…The results obtained in this experiment suggest that host malnutrition is directly responsible for the reduced egg laying and low maturation of S. mansoni eggs, leading to a decreased release of immunogens and thus affecting the expression of fibrogenic cytokines such as TGF-β1, in addition to IL-4, IL-10 and IL-13, as previously reported (Coutinho et al 2010). The low expression of fibrogenic cytokines, however, is sufficient to activate HSCs, but these cells in UI mice are unable to adequately synthesise type-I collagen.…”

“…It has been previously reported that schistosome-undernourished infected mice are able to develop a humoral immune response, but antibody titres are much lower than in control well-fed animals (Oliveira et al 2004, Coutinho et al 2010). The production of the cytokines interferon (IFN)-γ, IL-4 and IL-10 is lower in the UI mice, but in INOS-knockout mice, as infection progresses to the chronic phase, the kinetics of IFN-γ runs an antagonistic course when compared to that of WI animals (Ramos et al 2006).…”

“…Nutritional deficiency also influences the immune response and immunopathology of schistosomiasis in the murine experimental host (Coutinho 2004, Oliveira et al 2004, Coutinho et al 2007, 2010). …”

“…The production of the cytokines interferon (IFN)-γ, IL-4 and IL-10 is lower in the UI mice, but in INOS-knockout mice, as infection progresses to the chronic phase, the kinetics of IFN-γ runs an antagonistic course when compared to that of WI animals (Ramos et al 2006). On the other hand, the secretion of IL-13, a pro-fibrogenic cytokine, at the chronic phase, has been found to be at alternatively low and high levels of concentrations in splenocyte culture supernatants (Coutinho et al 2010). The Th2 cytokines and, in particular, IL-13 and the IL-13 receptor (IL-13Rα2) appear to be crucial for the hepatic fibrogenesis associated with schistosomal infection (Wynn et al 2004).…”

“…Undernourished-infected mice (UI) produce low levels of IL-4 (Oliveira et al 2004) and IL-13 (Coutinho et al 2010). …”